My iPhone suddenly won't work as a personal hotspot for my iMac

[DebbieL]

I have been using my iPhone as a personal hotspot to allow me to connect my iMac to the internet in the absence of any other connection (we moved house just as the lockdown began and we have no landline or fibre connection). I have a pay monthly contract and had to buy a 16GB data bolt-on to enable this - expensive, but needs must (I am supposed to be working from home). However, with more than 4GB still left of this bolt-on (according to the account info on MyO2), the iMac suddenly cannot connect to my iPhone. It can connect to my husband's iPhone, and my iPad can connect to my iPhone, so it doesn't seem to be a hardware or software issue. Having looked at the amount of data various devices in the household have used from my personal hotspot, my iMac has used the most, and it has used exactly 4GB before I stopped being able to use it. This makes me think there must be a hidden cap on the amount of data any one device can use, but I can't find any information about this on the O2 website, Aura was no help and I couldn't get through to an actual person on the phone. Does anyone in the community have any knowledge of this, please? 

[DebbieL]

@jonsie Ah, this is extremely helpful! I suspected something like this. I haven't had any communication from O2 but it seems very likely that I have triggered some automated blocker. I am, of course, not in my view breaching their fair usage policy, but I can see why my sudden heavy usage would raise the question. On the other hand, I have paid for my data bolt-on and am prepared to pay more for what I need, so it seems unfair to block my usage, if that is what is happening. I am living in a new house with no physical connection to the internet, and somehow have to make myself available to my employer for zoom meetings, download and upload documents and organise a backlog of emails which accumulated while I was moving house. I guess I'd better try to phone O2 and throw myself on their mercy. If you have any other ideas about how I might achieve a more reliable connection, I'd be grateful to read them. 

[jonsie]

It's probably the Zoom meetings rather than anything else you are doing.

To me, O2 renaged on their Unlimited data contracts when someone suddenly decided on the 4GB limit.

I'll have a look to see if I can find some of the old threads.

[jonsie]

A couple here @DebbieL 

https://community.o2.co.uk/t5/Pay-Monthly/O2-Fair-Usage-Policy-in-regards-to-mobile-data/m-p/1196303...

https://community.o2.co.uk/t5/Pay-Monthly/Pay-Monthly-4GB-Download-Monthly-Limit-unlimited-data-cont...

It may be as well getting a sim from another network if you have an old phone and just use it for tethering the iMac.

[MI5]

You've got 16gb to use that you've paid for.
That's your allowance, there is no fair use policy on limited tariffs, only unlimited ones.